There are 3 main types of AMR meters: direct, semi-direct and indirect. The type of meter used depends on the type of connection you have (low or high voltage) and on its power.
Direct AMR meter (low voltage)
All energy consumed passes through the meter. It measures the consumption directly without needing intermediate equipment, which makes it ideal for intensities up to roughly 100 A.
Mainly used in homes and small businesses, it is easy to install and maintain, and cheaper than an semi-direct meter.
Semi-direct AMR meter (low and high voltage)
The voltage is connected directly to the meter, but the current is reduced by current transformers (CT). It is particularly suited to intermediate intensities, generally between 100 A and 400 A.
It works perfectly for medium-sized commercial buildings and common areas of large buildings. It offers a lot of flexibility in managing high power ratings but requires additional equipment and extra setup.
Indirect AMR meter (high voltage)
Both the voltage and the current must be reduced by potential transformers (PT) and current transformers (CT) before they can be measured by the meter. This type of meter is designed to handle high intensities (powers greater than 250 kVA).
This meter is mainly used in industrial facilities, distribution stations or large buildings. The metering installation is capable of measuring very high currents and voltages, but requires additional equipment and regular calibration to ensure it stays accurate.
In summary
|
Meter type |
Connection |
Use | Equipment required |
|
Direct |
Low voltage, up to 100 A |
Homes, small businesses | No additional equipment |
|
Semi-direct |
Low voltage, from > 100 A to 250 A High voltage, up to 400 A |
Medium-sized businesses, commercial units | CT |
|
Indirect |
High voltage | Industrial facilities, large consumers | CT and PT |